1. We use brighten up when talking about the weather.
The weather brightens up if the sun starts to shine and the clouds begin to disappear.
Example of use:
I think it’s going to brighten up later.
2. To brighten up something or somewhere (or brighten something up) means to make it look better, perhaps with more colour or a fresh coat of paint.
Example of use:
Our kitchen was looking a bit dull so we brightened it up with some lovely yellow paint.
3. We also use brighten up to describe a person who suddenly looks or feels happier.
Example of use:
Maisie really brightened up when her mum arrived to collect her from school.
Image by notsogoodphotography
